Faithful Entanglement Purification for High-Capacity Quantum Communication with Two-Photon Four-Qubit Systems
Guan-Yu Wang, Tao Li, Qing Ai, Ahmed Alsaedi, Tasawar Hayat, Fu-Guo Deng · Physical Review Applied · 2018
$H\phantom{\rule{0}{0ex}}y\phantom{\rule{0}{0ex}}p\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}g\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}m\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}t$ (simultaneous entanglement of a system in several degrees of freedom) is an interesting quantum phenomena that attracts much attention for use in high-capacity quantum networks, but it is difficult to faithfully distribute hyperentanglement between distant network nodes. This study presents an efficient protocol for hyperentanglement distillation by designing fidelity-robust quantum gates, $i.e.$ parity-check quantum nondemolitions (QNDs) and SWAP gates, which guarantee that the protocol works faithfully and with high performance. Furthermore, these quantum gates can find application in faithful optical quantum information processing.